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Stock-Based Compensation - Performance Share Units (Details) - Performance share units - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining recognition period of unrecognized stock-based compensation costs			1 year 10 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested options (up to)	$ 15.0		$ 15.0
Long-term incentive plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeited (in shares)			11,819	10,572
Executive Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Executive Management \| Long-term incentive plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit granted to an executive (in shares)			144,097	28,060
Change in shares expected to be vested (in shares)	(18,865)	70,661
Vested (in shares)			0	6,874